Magnetic colloidal suspensions are used in numerous practical applications. However, their structural and dynamical properties are hardly known, particularly under an external applied field. For this purpose, an approachthat couples Brownian dynamics numerical simulations together with experimental measurements on tailored aqueous dispersions has been carried out. The use of scattering techniques, especially neutron scattering, enabled us not only to decipher the local structure but also to examine the translational dynamics at several length-scales. The effect of an external magnetic field has been measured and calculated parallely by the numerical simulation. Moreover, the rotational dynamics has been probed by magneto-optical birefringence relaxation measurements. The comparison between experimental and numerical results has improved the knowledge of the system, emphasising the role of the dipolar interaction.
